The overall objective of the studies supported by this grant is to elucidate the mechanisms by which dietary factors control or modify enzyme systems involved in lipid metabolism: 1. Test of an hypothesis that control of the levels of enzyme activities during peranatal development can modify the level of the enzymes. (a) A possible role of cholesterol in the milk of the suckling for establishing permanent control of serum cholesterol homeostasis. (b) A possible reduction in fatty acid synthetase and saturated acyl desaturase by unsaturated fat and cyclopropene fatty acids in perinatal nutrition. 2. The mechanism by which nonsubstrate levels of polyunsaturated fatty acids in the diet reduce the level of fatty acid synthetase. 3. Determination of adaptive and nonadaptive enzyme of glyceride synthesis.